1. Field of the Invention
This invention relates to emergency lighting units and pertains to those in which auxiliary lighting is provided by a battery source.
2. Description of the Prior Art
While emergency light units are available which provide illumination when line voltage fails, none has proved entirely satisfactory. Typically, the lighting unit is not lit when line voltage is operative and only lights when line voltage fails.
Accordingly, one object of this invention is to achieve lighting in response to line voltage as well as to battery voltage.
Auxiliary lighting sources which depend on battery power must provide some means for checking battery condition. Where the light source is enabled alternately by line voltage or battery voltage, some method is required for determining the respective states.
Accordingly, another object of this invention is to achieve instant indication of the status of line voltage and battery condition.